This invention relates to a meat packing apparatus of the type in which a shirred casing is connected to a nozzle from which meat is extruded to stuff the casing. The term "meat" as used herein is taken to mean all varieties of meat such as ham and sausage, as well as mixtures of meat, binder and other additives, which are extruded in the form of a viscous emulsion.
In the prior-art packing apparatus of the foregoing type, the shirred casing is supported while one end thereof is loosely fitted over the outer periphery of a nozzle. Pressure which is developed by stuffing the casing with meat extruded from the nozzle forms the casing into a straight, deshirred tubular configuration which is packed with the meat as the formation process proceeds. However, since a shirred casing is an extremely long casing which is shirred by being folded back on itself longitudinally at a multiplicity of points to effect a reduction in length, the wall thickness of the casing when in this shirred or folded state is large in comparison with the diameter of the casing when fully extended, i.e., deshirred. Since the nozzle is loosely fitted inwardly of the casing wall, a large difference develops between the inner diameter of the nozzle and the diameter of the straight tube into which the shirred casing is formed when the casing is extended by being stuffed with the meat. Owing to this large disparity in diameter, the meat extruded into the casing has a diameter which is much smaller than that of the straight, tubular portion, making it difficult to achieve tight packing of the casing. Proposed solutions to the problem are disclosed in Japanese Patent Application Laid-Open Nos. 50-32315 and 52-27715, which describe systems for stuffing a casing with meat by disposing a casing at a position forwardly of the direction in which meat is extruded from the nozzle and connecting the casing to the nozzle to effect the stuffing operation. In the disclosed arrangements, the casing is held sandwiched between an inner cylinder and an outer cylinder fitted over the inner cylinder. The casing is paid out toward the nozzle by driving the outer cylinder, with an assist from the action of an engaging member that engages the inner cylinder. Accordingly, the proposed arrangements have an extremely complicated operating mechanism and, being applicable solely to casings of a straight, tubular configuration, are not suitable for stuffing a shirred casing with meat.